Cryogenic transfer hoses, such as may be employed for transferring cryogenic gases and liquids to and from cryogenic tanks and modules, require substantial insulation for mitigating cooling losses and preventing the formation of condensation and ice on the hoses. Vacuums have been found to be very effective for providing cryogenic insulation. Thus, in order to achieve adequate insulation, conventional cryogenic transfer hoses are typically provided with a highly-insulative vacuum layer (commonly referred to as a “vacuum jacket”) intermediate a fluid transfer conduit and an outer jacket.
A problem that is commonly associated with cryogenic transfer hoses is that connective fittings that are used to attach the fluid transfer conduits of such hoses to cryogenic tanks and modules must also be insulated. Vacuum jacketed fittings for such applications are well known in the art, but such fittings must employ bayonet-style connections or other low-pressure connective means that do not require tightening by tools, because the outer jackets of vacuum-insulated fittings preclude access by tools. Vacuum-jacketed, bayonet-style fittings typically have a pressure limit of 100 to 150 PSI, which is too low for refrigerant-based cooling loop applications that typically operate at pressures exceeding 400 PSI.
High-pressure cryogenic transfer hose fittings, such as fittings that employ threaded connective elements, are also known in the art, but such fittings do not employ vacuum jackets because they must be accessible by tools for mechanical tightening (i.e. for establishing tight connections that can withstand high pressures). High-pressure fittings are therefore left “naked” (i.e. uninsulated) until they are connected and tightened, after which they are manually wrapped in foam or other bulky insulating materials. Such insulating materials must be unwrapped or cut away before the fittings can be disconnected. In addition to being time-consuming, cumbersome, and wasteful, manual installation and removal of insulating materials can be impractical for high-pressure applications in which space is limited, such as where a plurality of hose connections are spaced in close proximity to one another.
In view of the forgoing, it would be advantageous to provide an enclosure for a high-pressure, cryogenic transfer hose fitting that employs a highly-insulative vacuum jacket and that provides convenient access to the fitting for attachment and removal.